How Rehab Therapists Can Use the ICD-10 Code for Anxiety

Aside from perhaps some Applied Behavioral Analysis (ABA) clinics or mental health practices, generalized anxiety disorder (GAD) is generally not the first diagnosis that sits top-of-mind for most clinicians at rehab therapy clinics. However, many clinicians would agree that it can have a large impact on the outcome of a patient’s plan of care. This is why knowing the ICD-10 code for anxiety, when to use the ICD-10 code, and how best to apply it is crucial to accurately complete an evaluation and be reimbursed for the claim. 

What is Generalized Anxiety Disorder?

Before delving too far into the specific diagnosis code for GAD, let’s first define it. As with most medical diagnoses, there is more to it than just saying someone is anxious. The DSM V has a specific criteria list to determine if a person truly has GAD which reads:

1. The presence of excessive anxiety and worry about a variety of subjects (i.e., events or activities) that occur more often than not for at least six months.
2. The worry is reported as challenging to control. 
3. The anxiety and worry are accompanied by at least three of the following physical or cognitive symptoms (In children, only one of these symptoms is necessary for a diagnosis of GAD):

• Feeling restless or on edge,
• Being easily fatigued,
• Having difficulty with concentration,
• Being irritable,
• Having increased muscle tension, or
• Experiencing sleep disturbance (difficulty falling or staying asleep, or restless unsatisfying sleep).

What is the ICD-10 Code for General Anxiety Disorder?

GAD is found in chapter V under letter F of the ICD-10 coding structure. Specifically, the ICD-10 code for general anxiety disorder is code F41.1, but in the ICD-10 coding structure, specificity is the name of the game, be sure you affix the correct diagnosis as specified by the referring physician. For that reason, anxiety can be found in several other instances which include:

• F40.1: phobic anxiety disorder;
• F41.0 panic disorder;
• F41.9: unspecified anxiety disorder;
• F43.10: post-traumatic stress disorder, unspecified;
• F43.11: post-traumatic stress disorder, acute;
• F43.12: post-traumatic stress disorder, chronic; 
• F43.20: adjustment disorder, unspecified; 
• F43.21: adjustment disorder with depressed mood; and
• F43.23: adjustment disorder with mixed anxiety and depressed mood; 

When Would Rehab Therapists Use an ICD-10 Code for Anxiety?

Only on rare occasions would physical therapists, occupational therapists, or speech-language pathologists be using the ICD-10 code for anxiety as a primary diagnosis—maybe even never for most—but that does not mean the code doesn’t have a place in the plan of care or initial evaluation. If a patient’s anxiety is such that it can negatively impact the course of care, can later the patient’s prognosis for meeting their goals, or result in hospital (or other outside service) admissions, then anxiety should be applied as a secondary diagnosis for this patient. 

Why do you ask? Well, recall that there are now three levels of complexity for PT and OT evaluations, and SLPs have additional evaluation components to be aware of. For moderate to high complexity cases, an ICD-10 code for anxiety would be well suited to these types of patients.

John Wallace, PT, MS, OCS, Senior VP of Member Value and Chief Business Development Officer of RCM at WebPT, recently tackled the secondary diagnosis problem in his 2024 Combined Sections Meeting (CSM) presentation “People, Processes, and Internal Controls: Key Elements to Scaling Your Billing Operations.” Wallace recounted that far too many clinicians are short-changing themselves and their patients by affixing a low complexity evaluation CPT code to patients who would be better served as moderate or even high complexity—this could apply to cases of anxiety or even an additional musculoskeletal diagnosis like rheumatoid arthritis. To address the problem, Wallace encouraged clinicians to more accurately code patients' secondary and tertiary diagnoses. By doing so, he stated this will enable clinicians to better advocate for their value and be ready for increased emphasis by insurance payers on value-based care.

What Are Good Resources for Rehab Therapists to Find ICD-10 Codes?

In his presentation, Wallace encouraged rehab therapists to use their current EMR’s tools to search for the appropriate diagnosis, or—if necessary—look to outside assistance in the form of the free database ICD10data where over 69,000 codes can be searched. 

Are the ICD-10 Codes for Anxiety and Depression the Same?

Although most patient charts may state a patient has a diagnosis of anxiety and depression, their specific codes are not the same. Keeping to the specifics, the diagnosis of depression has its own code, under the grouping for F32. But just as anxiety has several other applicable ICD-10 codes, so does depression—so we created a separate post to go into more detail.

Why Is the ICD-10 Code for Anxiety Getting Denied?

As Wallace stated in his CSM presentation, many clinicians are still using ICD-10 incorrectly in their evaluations. And although we are over eight years removed from the jump from ICD-9 to ICD-10, the same mistakes continue. As a result, Wallace and the RCM team at WebPT have seen an uptick in Medicare audits and claim denials for improper use of ICD-10 codes. When ICD-10 was effective on October 1, 2015, the way clinicians applied diagnosis codes changed drastically. To allow for a steep learning curve, CMS gave clinicians a grace period on claim denials—well, post-pandemic, that grace period has long since ended, and clinics can no longer afford to make costly mistakes that can easily be fixed.

The first—and best—step Wallace recommended was to code for specificity. In ICD-9, the more codes a clinician applies to a case, the better, but now that ICD-10 has five times the number of codes, there should only be one primary diagnosis, and the secondary and tertiary ones must be specific to reflect the patient’s POC for rehab.

How Can Technology Help with ICD-10 Codes?

Aside from knowing how to assign the correct ICD-10 code to each patient’s case, there are many automated workflows that the best EMRs have built into their software. For example, WebPT uses an intuitive purpose-built Practice Experience Management platform for rehab therapists that eliminates extra clicks and the need to leave your software and do a Google search. After all, in today’s day and age, shouldn’t the software you use boost your practice experience?